Sildenafil Citrate

There is often a lack of attention among clinicians on the issue of sexual dysfunction related to antipsychotics. This may be based on the notion that schizophrenic patients have difficulty in maintaining relationships and therefore the issue of sexual dysfunction will not be a concern. However, with the emergence of newer antipsychotic agents with better efficacy and minimal extrapyramidal adverse effects, most schizophrenic patients are able to return to society and start their own family.

Among male patients, erectile dysfunction (ED) has been documented with the use of the first and new generation of antipsychotics. There have also been reports of cases of galactorrhea and breast engorgement which are the result of prolactin secretion secondary to the dopamine antagonist effect at the pituitary gland. The International Index of Erectile Function (IIEF) is a commonly used self-rated tool for assessment of male sexual dysfunction. The abbreviated version, IIEF-5, has been developed as a diagnostic tool for ED to complement clinical judgment.

Sildenafil citrate was introduced in 1990’s for the treatment of erectile dysfunction. Sildenafil is a potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5). Increased cGMP leads to smooth muscle relaxation (vasodilation) of arteries, followed by increased inflow of blood into the spongy tissue of the penis which causes an erection. In view of the difference between the mechanism of erectile dysfunction induced by antipsychotics and the action of sildenafil, there is uncertainty about the efficacy of sildenafil in this condition. An alternative treatment option which targets the mechanism of erectile dysfunction induced by antipsychotics may be required.

There have been reports of using stimulants for treatment of sexual dysfunction. The following is a case of antipsychotic induced erectile dysfunction that did not respond to sildenafil but recovered with methylphenidate treatment.